ICMS (Brazilian VAT) Calculator

ICMS: how the rate is applied

ICMS (Imposto sobre Circulação de Mercadorias e Serviços) is the Brazilian state tax that falls on goods and on transport and communication services. It is governed by LC 87/1996, the so-called "Kandir Law". At its core the math is just ICMS = base · rate. What changes is the internal rate, which each state sets on its own: São Paulo 18%, Rio de Janeiro 22%, Minas Gerais 18%, Paraná 19%, Rio Grande do Sul 17%, Bahia 19%. Most states sit somewhere between 17% and 19%. Electricity and telecommunications once climbed to 25–29%, until LC 194/2022 brought them back down to the standard rate. So a base of R$ 1,000 in SP taxed at 18% works out to R$ 180 of ICMS.

One quirk catches a lot of people off guard: the "by the inside" calculation. ICMS is part of its own taxable base, which means the nominal rate hides how much you actually pay. When you need to pull the ICMS out of a final price, the formula is ICMS = price · rate / (1 − rate). Then there is ICMS-ST (substituição tributária), where a single taxpayer in the chain collects the ICMS owed by everyone else. You see it a lot in fuel, beverages, cosmetics and auto parts.

Tax reform 2026–2032

EC 132/2023 and LC 214/2025 swap ICMS, ISS, PIS and COFINS out for a dual VAT built from IBS (state and municipal) and CBS (federal). The changeover stretches from 2026 to 2032, and the combined rate is expected to land around 26–27%. Both systems run side by side through that window, which is why you still have to calculate ICMS on every NF-e issued in 2026.

FAQ

Which rate should I use on an interstate sale? Apply the interstate rate, which is 4%, 7% or 12% depending on origin and destination. When the buyer is a non-taxpayer, add the DIFAL (rate differential) on top.

Why does my ERP (Bling, Tiny) show a higher effective rate than the nominal one? It comes back to the by-the-inside method. The tax sits embedded in the price, so once you measure it against the net value the effective rate always ends up above the nominal figure.

Does Simples Nacional pay ICMS separately? No. The unified DAS already folds in ICMS at a reduced rate. The exceptions are ICMS-ST and DIFAL on interstate purchases, which you pay separately.